Color developing solutions containing an aromatic primary amine color developing agent have been conventionally used in methods for forming color images and principally used in methods for forming color images in color photographs at present. However, these color developing solutions have a problem in that these are easily oxidized by air or in the presence of metals, and it is well known that when color images are formed by the use of an oxidized developing solution, an undesirable increase in fog and changes in sensitivity and gradation occur, and the photographic characteristics differ from those desired.
Accordingly, various methods for improving the preservability of color developing solutions have been investigated. Among them, a method in which a hydroxylamine and sulfite ion are used together is most commonly employed.
Further, in order to increase the stability of color developing solutions, various preservatives and chelating agents have been investigated. Such preservatives include aromatic polyhydroxy compounds as described in Japanese Patent Application (OPI) Nos. 49828/77, 160142/84 and 47038/81 (the term "OPI" as used herein refers to a "published unexamined Japanese patent application"), and U.S. Pat. No. 3,746,544,.etc.; hydroxycarbonyl compounds as described in U.S. Pat. No. 3,615,503 and British Pat. No. 1,306,176, etc.; .alpha.-aminocarbonyl compounds as described in Japanese Patent Application (OPI) Nos. 143020/77 and 89425/78, etc.; alkanolamines as described in Japanese Patent Application (OPI) No. 3532/79, etc.; and metal salts as described in Japanese Patent Application (OPI) Nos. 44148/82 and 53749/82, etc. Also chelating agents include aminopolycarboxylic acids as described in Japanese Patent Publication Nos. 30496/73 and 30232/69, etc.; organic phosphonic acids as described in Japanese Patent Application (OPI) No. 97347/81, Japanese Patent Publication No. 39359/81, and West German Pat. No. 2,227,639, etc.; phosphonocarboxylic acids as described in Japanese Patent Application (OPI) Nos. 102726/77, 42730/78, 121127/79, 126241/80, and 65956/80, etc.; and compounds described in Japanese Patent Application (OPI) Nos. 195845/83 and 203440/83, and Japanese Patent Publication No. 40900/78, etc.
However, hydroxylamines have a problem in that these generate ammonia by decomposition to cause the generation of fogs; and in addition, sulfite ions have a defect in that these competitively react with developing agents to injure the color forming properties of the agents. Accordingly, both of these agents cannot be said to be a favorable preservative. In addition, other preservatives are insufficient in the preservability or competitively react with developing agents to affect adversely the photographic characteristics such as sensitivity, and gradation, etc., and therefore, any satisfactory effect could not be attained as yet.
On the other hand, benzyl alcohol which is extremely effective as a color formation accelerator for color developing agents has widely been used in developing solutions for color photographic papers, and the use of the benzyl alcohol is an effective means for solving the problem of hindrance to the color forming properties, brought about by preservatives such as sulfite ions. However, the benzyl alcohol has various problems including environmental pollution and difficulty in the preparation of solutions. Accordingly, it is desired to develop some other technical means to avoid the use of benzyl alcohol.
However, the color forming properties of color developing solutions not containing the benzyl alcohol, which is a color formation accelerator, is inevitably deteriorated. Further, when conventional preservatives are used in such system containing no benzyl alcohol, some further extreme deterioration of the color forming properties of the color developing solutions would be presumed since most of conventional preservatives competitively react with developing agents to cause hindrance to the color formation.
In particular, the color formation of color photographic papers containing silver chlorobromide emulsions with high chlorine content is often hindered with during color development and these often have noticeable fog as described in Japanese Patent Application (OPI) Nos. 95345/83 and232342/84. Accordingly, in the use of such emulsions, the addition of some preservative which is hardly soluble in the emulsions and which has an excellent preservability even when no benzyl alcohol is used, is desired. However, such preservative has not been found as yet.